Elongated flexible tubular explosive



I Feb. 27, 1951 L. F. PORTER 2,543,057

ELONGATED FLEXIBLE TUBULAR EXPLOSIVE Filed April 30, 1946 INVENTOR Lou/sE PORTER ATTORNEY Patented Feb. 27, 1951 UNITED STATES PATENT OFFICEELONGATED FLEXIBLE TUBULAR EXPLOSIVE 2 Claims.

amended April 30, 1928; 370 0. G. 757) This invention relates toexplosive devices, and particularly to improved means for controllingthe action and manner of application of the forces generated by theaction of explosives. More particularly, the invention is concerned withpreformed explosives so encased and of such physical shape that theeffective forces of their explosion are largely directed inpredetermined directions, as a result of which such forces may be mostefficiently applied and a minimum of explosive may be employed toaccomplish a desired object, with less danger of injury to surroundingobjects or personnel, andwith less unwanted damage to portions of thetarget or object worked upon other than the parts whose destruction orthe penetration of which may be desired.

The method of directing an explosive blast in a given direction,variously known as the cavity effect, shaped-charge effect or Munroeefi'ect has been known and used for many years. Basically, this methodrequires that the explosive material be provided with a cavity facing inthe direction to which the blast is to be directed. Charges employingthis principle are commonly constructed in cylindrical form, with are-entrant cone which is to face the work. In order to achieve the mostefifective and concentrated blast, such cavity charges must be spacedfrom the work at the time of detonation, and their efiiciency is alsogreatly increased if the cavity is provided with a liner formed ofrelatively heavy material, such as a suitable metal; the cavity linerand explosive in combination provide a highly effective cutting agent.The principles involved in the nature and proportioning of the charge,the shape of the cavity, the proportions of the liner, and

v the stand-off distances required to achieve maxi mum penetration havebeen thoroughly investigated and are now well known to persons skilledin. this art. An important object of the present invention is to provideimproved means for applying the above-outlined principles to charges ofelongated or linear construction, whereby an elongated blast is producedespecially adapted to the smooth casing, which may be of rubber or thelike,

isolated stand-off or cavity-forming and explosive containing sections,these two sections being sepation. Upon explosion, the cavity liner andexplosive in combination provide a highly efiective cutting agent, inthe manner above-outlined. A related object is to provide such a dividerwhich altho of relatively heavy material is readily flexible with thecontainer to permit distortion of the linear charge in the mannerabove-mentioned while nevertheless retaining the explosive within theupper, charge-containing portion bf the casing and preventing escape ofany portion of the explosive into the cavity space. Other objects andadvantages will be apparent upon consideration of the disclosure in itsentirety.

In the drawings:

Fig. 1 is an end view of a mine casing, illustrating in side elevation alength of cavity charge material, constructed in accordance with thepresent invention, applied to the casing in such manner that the casingis adapted to be completely severed by explosion of, the charge;

Fig. 2 is a perspective view on a larger scale of a section of thelinear charge material, showing the means whereby end-abutting sectionsmay be joined;

Flig. 3 is a transverse section upon a still larger sca e;

Fig. 4 is a longitudinal sectional view taken substantially on line 4--4of Fig. 3 and looking in the direction of the arrows; and

Fig. 5 is a perspective viewof a portion of the flexible liner-dividerelement.

Referring now to the drawings, reference char acter l0 designates thehollow tubular container of my improved cavity charge. The container ispreferably made of resilient rubber or equivalent material, itscross-sectional contour being best shown in Fig. 3. As indicated in thelast-mentioned view, the casing is preferably of rectangular sectionexcept for its top, which may be rounded, a. flat bottom being providedto lie against the work, and substantially parallel side walls. It willbe perceived, however, that the precise contour is subject to variation.One or more pairs of horizontally opposed grooves l2 are provided in theinterior surfaces of the side walls, adapted to receive-the out-turnedflanges l3 of the metallic divider assembly generally designated IS inFig. 5. The divider is formed of a metallic channel, the precise shapeand angular relationship of the sides of which may be varied to suit theblast characteristics desired. In the illustrative embodiment shown thesides of the divider are disposed at an angle of approximately 80 withrelation to one another. Flexibility is rated by a flexible, metalliccavity-defining partiimparted to the channel assembly by a plurality 3of relatively thin slots is extending transversely therethrough atrelatively close and regular intervals from the apex to points adjacentthe edges of the flanges i3. The extreme edges, of the flanges are leftintegral, however, to tie together the sections formed by the slots.Over the slotted divider is laid a continuous flexible membrane l7 oi!rubber or the likewhich serves to seal the slots .suitable plugs as 22through which primer detonator assemblies as 24 may project. These maybe electrically operable, as indicated, and may also serve to conductthe explosive wave from one section to the next by direct detonation ofone another where sections are joined as in Fig. 2. The sidewalls of thelower portion or the tubular casing serve as stand-off means, to holdthe charge and the cavity-defining divider or liner away from the work aproper distance. The sidewalls of the lower portion are preferablythicker than those of the upper portion, as clearly shown in Fig. 3, toprevent collapse of the walls where the, charges are used under water,although it will be apparent that reinforcement may be employed as ameans for stiffening the walls of the cavity section. The walls mayconveniently be made of a rubber material of sumcient stiflfnes's andthickness that the lower portion will withstand external hydrostaticpressure of the order of 40 p. s. i. without greatly impairing itsflexibility. The upper section of the tube is, of course, reinforced bythe contained explosive and is preferably made thinner, as shown, forcompactness and maximum flexibility.

The force of the explosive blast derived from linear cavity chargesconstructed in accordance with my present invention may be so preciselypredetermined that very accurate cutting may be effected without anygreat danger to nearby structures provided the normal precautions aretaken when using explosives. In the typical operation illustrated inFig. 1, sections of the linear charge have been wrapped around thecasing of a mine 25. The wires 21, suitably connected to one of theprimers 24, are conducted to suitable energizin and firing means (notshown) for initiating theblast in the well-known manner. has been foundthat by the use of charges constructed and arranged in this manner,encased explosives such as the mine 25, when filled with explosivematerials of the types ordinarily used, and when not equipped withanti-disturbance devices, may be severed and completely opened withoutdetonating the explosive charge of the mine or other encased explosive.The present invention may be used to cut or sever explosives or 1:Zrnytype derelict completely submerged in we While it will be apparent thatthe preferred embodiment of my invention herein disclosed is wellcalculated to fulfill the objects first above stated, it will beapparent that the invention is susceptible to variation, modificationand change within the spirit and scope of the subjoined claims. Y

/ The invention herein described may be manu- -factured and used by orfor the Government of the United States of America for governmentalpurposes without the payment of any royalties thereon or therefor.

I clahn:

1. An elongated flexible tubular container, a

flexible partition extending longitudinally therethrough and dividingthe same into a lower, cavity and stand-01f portion and an upper,explosive containing portion, said partition being contoured to impart acavity charge effect and being of sectionalized metallic constructionand of angular cross-section, out-turned flanges carried by the marginsof said partition, the .inter-.

nal walls of said tubular container being provided with slots intowhichthe flanges fit, and a quantity of explosive within said upper portion2. An elongated flexible tubular container, 9. flexible partitionextending longitudinally therethrough and dividing the same into alower, cav- REFERENCES CITED The following references are of record inthe file of this patent:

UNITED STATES PATENTS Number Name Date Punshon Apr. 29, 1884 Holm July23, 1946 Greulich Oct. 22, 1946 FOREIGN PATENTS Number Country Date to163 of the Explosives Engineer, July-August,

1945. (Copy in Division 30.)

Boles Nov. 11, 1873 Great Britain 1911

